Gas turbines are continuously being modified to increase efficiency and decrease cost. One method for increasing the efficiency of a gas turbine includes increasing the operating temperature. Increases in operating temperature result in more extreme operating conditions which have led to the development of advanced super alloy materials and complex coating systems designed to increase the heat tolerance of the turbine components and protect the turbine components from reactive gasses in the hot gas path of the gas turbine.
The temperature tolerance of a turbine component may also be increased through the use of cooling channels. Cooling channels are typically incorporated into the metal and ceramic substrates of turbine components used in high temperature regions of gas turbines. Cooling holes are masked before the component is coated with a thermal barrier. The masks prevent materials from plugging cooling holes during the coating process. Existing techniques for masking cooling holes include manually inserting plugs into the cooling holes before the coating process and manually removing plugs after the coating process. Another known technique injects a gel that solidifies into each cooling hole to mask the cooling holes during the coating process. After the coating process, the gel is removed. Another known technique plugs the cooling holes by welding a plug in each cooling hole. After the coating process, removal of the plugs causes damage to some of the cooling holes or surrounding area that requires additional processing to return the cooling holes or the surrounding area to operational condition. A mask process that can with high reliability and repeatability identify, mask and unmask cooling holes would be desirable in the art.